# std::chrono::treat_as_floating_point

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< cpp‎ | chrono

Defined in header `<chrono>` |  |
template< class Rep > struct treat_as_floating_point : std::is_floating_point<Rep> {}; |  | (since C++11)

The `std::chrono::treat_as_floating_point` trait helps determine if a duration can be converted to another duration with a different tick period.

Implicit conversions between two durations normally depends on the tick period of the durations. However, implicit conversions can happen regardless of tick period if std::chrono::treat_as_floating_point<Rep>::value is true.

### Helper variable template

template< class Rep > constexpr bool treat_as_floating_point_v = treat_as_floating_point<Rep>::value; |  | (since C++17)

### Specializations

`std::chrono::treat_as_floating_point` may be specialized for program-defined types.

### Example

Run this code

    #include <chrono>
    #include <iostream>
    #include <thread>

    void timed_piece_of_code()
    {
        std::chrono::milliseconds simulated_work(2);
        std::this_thread::sleep_for(simulated_work);
    }

    int main()
    {
        auto start = std::chrono::high_resolution_clock::now();

        std::cout << "Running some timed piece of code...\n";
        timed_piece_of_code();

        auto stop = std::chrono::high_resolution_clock::now();

        // A floating point milliseconds type
        using FpMilliseconds =
            std::chrono::duration<float, std::chrono::milliseconds::period>;

        static_assert(std::chrono::treat_as_floating_point<FpMilliseconds::rep>::value,
                      "Rep required to be floating point");

        // Note that implicit conversion is not allowed here
        auto i_ms = std::chrono::duration_cast<std::chrono::milliseconds>(stop - start);

        // Note that implicit conversion is allowed here
        auto f_ms = FpMilliseconds(stop - start);

        std::cout << "Timing stats:\n";

        std::cout << "  Time in milliseconds, using default rep: "
                  << i_ms.count() << '\n';

        std::cout << "  Time in milliseconds, using floating point rep: "
                  << f_ms.count() << '\n';
    }

Possible output:

    Running some timed piece of code...
    Timing stats:
      Time in milliseconds, using default rep: 2
      Time in milliseconds, using floating point rep: 2.57307

### See also

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